Objectives
The aim is to identify the evolution of self-assessed anxiety, pain, fatigue, and relaxation states of cardiac surgery patients before and after using hypnosis, virtual reality and virtual reality hypnosis as compared with a control group.
Registration
This trial was registered on clinicaltrials.gov with the trial identification number NCT03820700 (https://clinicaltrials.gov/ct2/show/NCT03820700). Registered on 29 January 2019. Retrospectively registered. The recruitment started in October 2018 and closed in January 2020. Registration was prospective before enrolling the first patient. The complete protocol of the study has previously been published and displayed detailed information about the study design, the recruitment procedures, and the assessment and intervention components (29). Therefore, we will only summarize these aspects in this section.
Recruitment and patient involvement
Patients and public were involved at several stages of the trial, including the choice of the questionnaires and the evaluation of the virtual reality setting. The final study protocol was designed beforehand thanks to pilot participants. There is no plan to individually identify and notify patients about the results of this study.
Randomization was done with blocks of 5 before initial contact with patients. Initial contact between the investigator and the patient took place one day before cardiac surgery, at the hospital. Patients included were adults undergoing cardiac surgery (coronary artery bypass graft (CAB); mitral valve replacement (MVR); aortic valve replacement (AVR); others) who have given consent for their participation. All the study and surgeries were conducted in the University Hospital of Liege (Belgium). Inclusion criteria were the following: adults (> 18 years), French speaking, undergoing cardiac surgery, Glasgow Coma Scale score > 14,(30) Richmond Agitation-Sedation Scale score comprised of -1 and + 1 (31). Exclusion criteria were the following: psychiatric diseases, claustrophobia, acrophobia, heavy hearing or visual impairment, extreme fatigue, verbal incoherence, surgery cancelled or postponed. After explanations about the tools used, patients included were asked to participate to the study and fill in the consent form. They answered to the investigator’s questions and had a session of one technique in their hospital room and another after the surgery.
Intervention components
This study is a prospective randomized study, single-center trial with four arms, including three experimental groups and one control group. Participants were randomly included in the following conditions:
(1) Control group: daily standard care.
(2) Hypnosis: daily standard care combined with 20-minutes hypnosis session. Hypnosis exercise was created and recorded by M-E Faymonville and A-S. Nyssen, both experts in clinical and experimental hypnosis. The recording, named “Soothing white clouds”, included suggestions about relaxation, positive body sensations, invitation to observe a sunrise and a beautiful landscape meanwhile relaxing in a white cloud chair.
(3) Virtual reality (VR): daily standard care combined with VR session. Investigator used a head-mounted 3D graphical display with goggles, created by Oncomfort ©. With this tool, participants watched a 3D immersive landscape for 20 minutes consisting of a shed near a lake at sunrise followed by a relaxing moment in the clouds. The session ends on the lake's edge (Fig. 1).
(4) Virtual reality hypnosis combination (VRH): daily standard care combined with VRH session. Soothing white clouds hypnosis session was combined to 3D visual movie (immersive landscape and relaxing moment in the clouds by Oncomfort ©), with a duration of 20 minutes.
Assessment
Demographic data were recorded (age, gender, type of surgery, alcohol and tobacco use) as well as psychological measures (anxiety, pain, fatigue, relaxation) and physiological data (heart rate, arterial pressure, respiratory rate, oxygen saturation, pupil size). The primary outcome, anxiety, was assessed with the Visual Analogic Scale (VAS) before and after the 20 minutes’ sessions of the intervention. Secondary outcomes measured with VAS are pain, relaxation and fatigue. The VAS score helps to determine the intensity of these variables, as subjectively assessed by the patient, on a scale ranging from 0 to 10. Physiological parameters such as heart rate, arterial pressure, respiratory rate, oxygen saturation, pupil size were recorded directly on the patient’s bed monitor. Demographic factors have been also recorded and included in analysis: age and gender, surgery time, cardiac surgery type (aortic valve replacement, mitral valve replacement, coronary artery bypass surgery, other), alcohol consumption, use of tobacco, medication. Daily dissociative profile of participants have been assessed with the Dissociative Experience Scale (DES) 28-items (32). Hypnosis, VR, VRH or nothing (control group) were applied for 20 minutes’ sessions: the day before surgery (Day-1 at 5 pm) and the day after (Day + 1 at least 24 h after surgery). Before and after the session, physiological and psychological parameters were recorded (See Fig. 2).
Statistical analyses
The sample size calculation was based on repeated measures ANOVA test. Alpha was set at 0.05, power at 95% and the standardized effect size at 0.5. Studies which aim to assess the effect of hypnosis on the patients’ pre-surgery anxiety considered that an effect size of 0.2 was considered small, 0.5 moderate and 0.8 large (1). According to this analysis, 12 patients are required in each group for a total of 48 patients. We decided to enroll one hundred patients (25 per group) to compensate possible dropouts on the postoperative day. Normality was investigated graphically with histogram and quantile-quantile plot and was tested by using the Shapiro-Wilk test. Continuous variables were reported as means (± standard deviation) or medians (interquartile range) for skewed distributions, while the number and percentages were given for qualitative variables. Homogeneity of the four groups were assessed with Chi-squared Test for qualitative and dichotomous variables and with a one-way analysis of variance (ANOVA-1) or the non-parametric Kruskal-Wallis test for the quantitative variables. A repeated measures ANOVA test was used to compare the evolution of the parameters between Day − 1 and Day + 1 morning and afternoon according to the groups. This analysis was adjusted by the potential confounding factors. Calculations were always carried out on the maximum number of data available. Results were considered as statistically significant at the 5% critical level (p < 0.05). Analyses were performed using R 3.5.3 (R Core Team) and the package Rcommander (Rcmdr) and using SAS 9.4 (© SAS Institute Inc., Cary, NC, USA).